Apparatus for testing airbrake control valves

ABSTRACT

Apparatus is provided for testing airbrake valve portions. The apparatus features a fluid-operated brake clamp to confine the airbrake control valve portion by applying sealing pressure to the airbrake portion from a pivotable C-clamp which is free to move longitudinally with respect to the airbrake portion. In addition, the apparatus includes a device for confining and locating the airbrake control piston via a controlable piston stop contained within a sealed chamber. Several air control valves in the test apparatus are activated automatically, and substantially the entire test program is conducted on automatic control.

United States Patent [72] Inventor James G. Rees 105 Industrial Road,Hammond, lnd. 46320 [21] A-pp1. No. 821,801 [22] Filed May 5, 1969 [4S]Patented Aug. 3, 1971 [54] APPARATUS FOR TESTING AIRBRAKE CONTROL VALVES8 Claims, 7 Drawing Figs.

I 52] [1.8. CI. 73/39, 269/27 [51] Int. Cl. 601m 3/26 [50] FieldolSearcl! 73/39, 118; 269/25, 27, 30; 33/180, 181, 185

[56] References Cited UNlTED 'STATES PATENTS 1,037,626 9/1912 Hogle269/77 X 1,273,319 7/1918 Blakely 269/77 X 1,787,509 1/1931 Campbell73/39 1,997,749 4/1935 Safford 73/39 2,032,121 2/1936 Farmer.... 73/392,103,305 12/1937 Thomas... 73/39 3,169,391 2/1965 Spalding 73/393,290,039 12/1966 Lancaster 269/25 3,452,591 7/1969 Phillips et al.73/118 Primary Examiner- Louis R. Prince Assistant Examiner-William A.Henry, 11 Attorney-Wolfe, Hubbard, Leydig, Voit & Osann ABSTRACT:Apparatus is provided for testing airbrake valve portions. The apparatusfeatures a fluid-operated brake clamp to confine the airbrake controlvalve portion by applying sealing pressure to the airbrake portion froma pivotable C-clamp which is free to move longitudinally with respect tothe air brake portion. In addition, the apparatus includes a device forconfining and locating the airbrake control piston via a controlablepiston stop contained within a sealed chamber. Several air controlvalves in the test apparatus are activated automatically, andsubstantially the entire test program is conducted op automatic control.

PATENIEB m3 iHZl SHEET 1 Bf 3 PATENTEDmsa I97: 3 596 500 sum 3 OF 3APPARATUS FOR TESTING AIRBRAKE CONTROL VALVES BACKGROUND AND OBJECTSThis invention relates to apparatus for testing railway brake controlvalves, and more particularly concerns the provision of apparatusadapted to facilitate and automate programmed tests of such valves.

Once every four years, the Association of American Railroads and theInterstate Commerce Commission require that each airbrake on freighttrains be removed from the train and subjected to a sequence offunctional tests. The airbrake control valve, divided into the serviceportion and the emergency" portion, is tested on a manual test stand,with each brake control valve portion being subjected to variousmovement resistance, leakage, port capacity, and charging rate tests.

These tests are more or less standard, and are described in InstructionPamphlet No. 5039-19, Feb. 1962, entitled Code of Tests, AB FreightEquipment Valves, The AB Test Rack, as adopted by the Association ofAmerican Railroads," published by the Westinghouse Airbrake Company,Airbrake Division, Wilmerding, Pennsylvania. The freight brake itself isdescribed in Instruction Pamphlet No. 5062, Dec. I945, The AB FreightBrake Equipment, also published by Westinghouse. The test rack is alsodescribed in Thomas US. Pat. No. 2,103,305. These Instruction Pamphletsare incorporated by reference herein.

conventionally, the airbrake control valve is disassembled into itsservice portion and its emergency portion, and each of the respectiveportions is tested on the manual device described in InstructionPamphlet No. 5039-19.

The sequence of tests is extremely complex. The conventional testingdevice includes an array of manually controlled valves, pressure gauges,and the like, all of which must be operated in a designated sequence soas to subject each valve portion to the prescribed battery of tests.This sequence is complicated, and is time consuming even for trainedoperators. Moreover, it is difficult to train the operators, andconsequently labor cost represents a substantial fraction ofbraketesting expense. It is accordingly an object of the invention toprovide an apparatus for automatically conducting the test. Conventionalmanual testing of brake control valves has other serious disabilities.For one thing, the test operator must visually monitor the variouspressures and rates, with the attendant possibility of error due topersonal judgment at best, or the likelihood of overlooking a faultyvalve at worst. Thus, if a malfunction is overlooked, the defectivevalve is returned to service. On the other hand, if a properlyfunctioning valve is erroneously reported as having failed one of thetests, the resulting disassembly and repair of the control valve is bothunnecessary and expensive. It is another object of the invention toprovide a testing apparatus completely free of the possibility ofindividual error in conducting the test sequence.

The conventional test sequence and test apparatus have long beenrecognized as necessary but awkward. The test operator is required toobserve rather large pressure drops for either short periods or for longperiods. If the time is short, the pressure drop is difficult toobserve; if long, the procedure is slow. Furthermore, for some of thetests it is necessary for the operator to observe pressures on twogauges simultaneously and note the difference. The possibility of errorin determining small differences between large numbers is self evident.A further object of the invention is to provide automatic apparatus forshortening the time but increasing the reliability of airbrake controlvalve-testing equipment.

Additionally, the airbrake control valve test assembly that is commonlyemployed itself requires frequent scheduled validation, of itscomponents. Instruction Pamphlet No. 5039-19 contains an extensivesection of test rack validation procedures to periodically insure theaccuracy of air pressure gauges, other assorted equipment, and thenonexistence of leaks and other malfunctions which would mitigateagainst providing accurate control valve tests. Also, the conventionaltest apparatus must be disassembled, cleaned, and lubricated quitefrequently. Another object of the invention is to provide an improvedcontrol valve test assembly which is less subject to test assemblymalfunction.

Certain of the conventional valve test assembly components areparticularly awkward. Perhaps outstanding in this respect is the meansfor attaching the airbrake portion to the test rack itself. Although tosome extent the air brakes manufactured by different companies areinterchangeable, it has heretofore not been possible to provide foruniversal adapters by reason of the significant differences among valvesmade by different manufactures and, in some cases, between differentmodels of valves made by the same manufacture. In addition, differentadapters are necessary for the control and for the emergency portions ofthe airbrake control valve. It is therefore a further object of theinvention to provide an improved airbrake clamping device wherebyairbrake portions made by different manufacturers, as well as both theservice and the emergency portions, may be readily be accommodated onthe same test stand.

Additionally, for certain tests in the sequence of testing the airbrakecontrol valves, it is necessary to confine and locate an internal pistonin the valve. Previously this confining and locating action has beenawkward, imprecise, and tedious. An ancillary object of the invention isto provide an improved apparatus for confining and locating the internalpistons of rail way brake control valve at designated stages of the testsequence.

Still another object is to provide a test device in which each of theprogrammed tests is reported as an absolute pass or fail on a permanentrecord. Another object is to provide an automatic control system forrailway airbrake control valve tests which integrates test sequencecontrol, valve regulation, electrical and/or electronic circuitry, andpneumatic flow and pressure measurement.

Other objects, aims, and advantages of the invention will becomeapparent as the following description proceeds.

While the invention is susceptible of various modifications andalternative forms, a specific embodiment thereof has been shown by wayof example in the drawings and will herein be described in detail. Itshould be understood, however, that it is not intended to limit theinvention to the particular form disclosed, but, on the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as expressed in theappended claims.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 schematically depicts the airbraketest assembly, in this case with the service portion of a WestinghouseAB" freight equipment valve in position;

FIG. 2 is an elevation of the clamping device used to mount the airbrakeportion to the test rack;

FIG. 3 is a top view ofthe clamping device;

FIG. 4 is an end view of the clamping device, taken along plane A-A ofFIG. 2;

FIG. 5 is an enlarged elevation of the apparatus for confining andlocating an internal piston of the brake control valve during testing;

FIG. 6 is a sectional view, corresponding to FIG. 5, showing thefunctional components of the confining and locating apparatus;

FIG. 7 is an end view ofthe apparatus of FIGS. 5 and 6.

DETAILED DESCRIPTION Turning first to FIG. l, a schematic flow andpressure con trol and monitoring system is depicted corresponding to thesystem employed both with conventional test racks and with the apparatusaccording to the invention. As indicated in the drawing, thediagrammatic piping arrangement is adapted to apply compressed air tothe various numbered ports extending to a portion of the airbrakecontrol valve, here depicted as the service portion 11, via an uprightbracket 12 and an adapter plate 14 (FIG. 2), shown in FIG. 1 as a singleelement 12, 14.

The various conduits communicating via the elements 12, 14 extends to aseries of control valves arranged on a panel, the individual valvesbeing operated manually in a conventional test rack and by solenoidcontrol in the system of the present invention.

The array of valves bear numbers corresponding to the conventionalnumbering system used with the Westinghouse test rack, that is, readingfrom right to left and then from top to bottom, numbers: 15, 19, 20, 13,12, 3, and 4 on the top row; 9,7, 18, 14, 17, and 11 on the middle row;and 1, I6, 2, 9, 5, and 6 on the bottom row. Valves 7, 18, 14, and 17connect with chokes or throttles, respectively number 63 drill size,number 73 drill, number 50 drill, and three-sixteenths drill. Similarly,valve number 22, connecting to the brake-type reservoir 15, leads to anumber 30 drill choke.

Several additional valves are included in the system depicted in FIG. 1.Conventionally, valve A is a rotary valve, described at pages 22 and 23of Instruction Pamphlet No. 5039-]9. In keeping with the present system,where all of the valves are activated by solenoid control on pneumaticdiaphragm valves, valve *A" is removed and in its place the solenoidvalve combinations are used. By the same token, valve B, a manual valvein the conventional test rack, is replaced with a series of solenoidvalves. In all functional respects, however, valves A and B operateidentically irrespective of whether they are manually or automaticallycontrolled.

At the top of FIG. 1 are shown a series of pressure gauges 16,corresponding to the pressure gauges used in the conventional test rack.Reading from left to right, these gauges 16 are the main reservoirpressure, quick action chamber pressure, brake pipeline pressure, brakepipe volume, auxiliary reservoir pressure, brake cylinder reservoirpressure, secondary quick service pressure, and emergency reservoirpressure gauges. The various reservoirs shown in FIG. 1 similarlycorrespond to those in the conventional test rack assembly, and aparticular advantage of the present invention is that an existing testrack provides all but the automatized components for a test rack systemas described herein. Thus, the test rack equipment includes a mainreservoir 18, an emergency reservoir 19, an auxiliary reservoir 20, abrake cylinder reservoir 21, and a quick action chamber reservoir 22.

As will be described presently, it is possible, under the control of thetest program-sequencing controller, to connect any of the internal testpressure singly or in pairs to the pressuresensing system represented bythe gauges 16 in FIG. 1. In keeping with the invention, thepressure-sensing system com prises four pressure difference switches,each containing two separate and adjustable circuits permitting avariation of eight pressure differences. One of the pressure differenceswitches has an adjustable setting under the control of the operator,who adjusts the setting when switching the present test rack for a teston one type of valve to another. In addition, the pressure-sensingsystem contains five dual setting, single pressure switches, whichallows up to ten different pressures to be read. Thus, by reading thedifference between two pressures, typically the difference between theauxiliary and main reservoir pressures, or by timing the opening andclosing of the various valves, the pressure drop or pressure increaseover a given period of time is readily determined. This, it will beappreciated, is performed in the same manner as a manually operatedconventional test rack.

The manometer 24 on a conventional system is advantageously replacedwith two pressure-sensing transducers, each provided with an adjustablepressure setting controlling a two-pole double-throw relay. Sensing ofpressure differences is photoelectric, and the signal is amplified by asolid state amplifier.

Turning now to FIGS. 2, 3 and 4, testing is initiated by clamping arailroad airbrake portion 11 onto the test stand, represented by base25. Extending from the base 25 is an upright bracket 12, onto which isremovably secured an adapter plate 14. Ordinarily, a series of adapterplates is employed, one each corresponding to the emergency and theservice portions of a railway airbrake control valve, with as manyadditional adapters 14 as may be required to accommodate brake portionsof different designs.

To mount the valve portion 11 onto the adapter plate 14, a series ofbrake-engaging studs is provided on the airbrake-portion-facing surfaceof the adapter plate 14. These studs, not shown in the drawings, projectpartly into a series of bolt holes in the airbrake valve portion 11normally used to mount the portion 11 onto the complete airbrakeassembly (see Instruction Pamphlet No. 5062).

Axially aligned with each of these studs is a series of pressure pointrods 26 (FIG. 4), in this case there being three such pressure pointrods 26. The rods 26 each have abutting ends 28 to apply pressure ontothe portion 11 in a direction toward the adapter plate 14 and theupright bracket 12. The pressure point rods are threaded into tappedholes in an equalizing adapter pressure plate 28, and this plate 28 inturn is pivoted on a pivot 29, best shown in FIG. 3, to an abutment endplate 30.

Clamping is afforded by applying compression to remote ends of acarriage 31, which include a pair of spaced apart, generally C-shapedclamp sides 32 arranged to straddle the upright bracket 12 and theairbrake portion 11, and at the same time to facilitate insertion andremoval of the airbrake portion 11 at the beginning and end of each testsequence, respectively. The end plate 30, which carries the pressurepoint rods 26 (FIG. 2) is welded to one end of the clamp sides 32, whichend will hereinafter be referred to as the free, or abutment, end.

The opposite end of the carriage 31 is arranged to pivot about an axleor fulcrum 34, contained in a bearing 35. In turn, the bearing 35 ismounted in a crosshead 36 so that the bearing 35 is free to move towardand away from the upright bracket 12 in a perpendicular or normaldirection thereto.

Pressure is applied to clamp the control valve portion 11 onto theadapter plate 14, and this in turn onto the upright bracket 12, from afluid (either hydraulic or pneumatic) operated piston, or other drivemechanism, 38, supplied with high-pressure fluid via conduit 39 (FIG.3). The piston rod 40 extends to a pressure plate 41, which in turnextends via a pair of eye bolts (best shown on FIG. 5) 42 connected tothe upright bracket 12.

It will be appreciated, therefore, that pressure from the piston 38 tothe piston rod 40 applies pressure onto one side of the upright bracket12, whereas this pressure is opposed by the abutment end plate 30 of theopposite end of the carriage 31. As compression is thus applied, theabutment end of the carriage 31 tends to move toward the upright bracket12 while gaskets (not shown) between the upright bracket 12 and theadapter plate 14, and between the adapter plate 14 and the valve 11, arecompressed. However, the bearing 35 and the crosshead 36 permit theentire carriage assembly to move perpendicularly with respect to theupright bracket 12 so that no torque is applied to the bracket 12.

One feature of the carriage 31 has been found to be especiallyadvantageous in connection with the present invention. As the assemblyof the carriage 31, the piston 38, and all related'components isjournaled about the axle 34, the entire assembly tends to remain ineither the valve-engaged or the valve-disengaged position. This isaccomplished by so proportioning the various components that the centerof gravity of the entire pivoting assembly is located above and to theright of the axle 34, as seen in FIG. 2. The center of gravity, however,is located so that as the carriage 31 is swung in a counterclockwisedirection, as viewed from the aspect of FIG. 2, it moves to the left ofthe axle 34, thereby keeping the carriage 31 in a valve-disengagedposition without the use of springs, counterweights, or the like.

To employ the clamping device shown in FIGS. 2, 3, and 4. an adapterplate 14 is placed into position on the upright bracket 12. The carriage31 is then swung into position, and the pressure point rods 26 areadjusted to abut against the control valve portion 11; preciseadjustment of the pressure point rods 26 is unnecessary, since theequidistant positioning of the several rods 26 about their central pivot29 insures the 7 application of equal pressure irrespective of slightmisadjustment of the pressure point rods 26.

For clamping the various components into place, it is only necessarythat pressure be applied via fluid pressure conduit 39 (FIG. 3) to thepiston rod 40. Conversely, to unclamp the valve portion 11 from theassembly, pressure is withdrawn from the fluid pressure conduit 39, thepiston rod 40 retracts, the carriage 31 may be swung free of the valveportion II, and the valve portion removed.

One other feature of the clamp is worthy of mention. To insure that theclamp carriage 31 is positioned accurately with respect to the valveportion 11. that is to insure that pressure is applied perpendicularly,an adjustable locating rod 44 is provided at the abutment end of theclamp sides 32. This regulates the angular position of the carriage 31.The locating rod 44 may, as shown, be secured to the carriage 31 or,alternatively, it may be mounted onto the base 25.

Turning now to FIGS. 5, 6 and 7, an apparatus is shown for confining andlocating an internal piston of the railway brake control valve duringtesting. For some test procedures, it is necessary that a piston in theairbrake control valve portion be immobilized or otherwise preventedfrom moving excessively in one direction. Conventionally, a piston stopcover is unboited from the air-brake control valve portion 11 and apiston stop. utilized to immobilize the piston. This however requiresremoval of the piston stop cover and replacement of the cover after thetest has been concluded. In keeping with the invention, a confining andlocating apparatus is provided which includes a stop stem 45 having acollar 46 at its external end. The internal end, not shown, is threadedinto the conventionally tapped hole of a piston locatedwithin theairbrake control valve portion 11.

A pressuretight housing 47 is connected to the valve portion 11 via anannular resilient gasket 48. Clamping pressure to secure thispressuretight relationship is applied by tightening the nuts 49 on thepair of eye bolts 42 (see also FIGS. 2 and 3) connected to the pintle43. It will be recalled that pressure from the piston 38 (FIG. 2) isapplied to the pressure plate 41, and from there to the control valveportion 11, when the clamp of FIGS. 2, 3 and 4 is in itspressure-applying position.

The pressuretight housing 47 includes a stop stem cavity 50 that housesa linkwork mechanism for engaging and disengaginga piston stop 51 withthe piston stop stem collar 46. The pistonstop 51 is an invertedU-shapcd member which straddies the piston stop stem 45 and whichprevents the piston (not shown) within the valve portion 11 fromwithdrawing the piston stop stem 45 when the piston stop 51 is in theposition shown in FIG. 6.

Engaging and disengaging of the piston stop 51 from its position withrespect to the piston stop stem 45 is effected with a linkwork includinga bellcrank or arm 52, with the piston stop 51 hanging from a pin at theremote end of one arm. The arm of the bellcrank 52 is adjustable bymeans of the threaded screw 54 for accurate positioning of the pistonstop 51.

The combination of the bellcrank 52 and the piston stop 51 isconstructed so that gravity urges the piston stop 51 into an engagedposition with the piston stop stem 45. When, however, for parts of avalve test procedure when it is desired that the piston within the valveportion 11 be free to withdraw into the portion 11, a fluid-operatedactuator is provided for activating the bellcrank 52. As shown in FIG.6, the actuator includes a piston cylinder 55, and a piston 56 withinthe cylinder having a piston rod 58 extending from the piston and intooperative engagement with the bellcrank 52. Both the piston 56 and thepiston rod 58 are provided with O-ring or other fluid seals.

A spring 59 normally urges the piston 56 into engagement with thelinkworlr or bellcrank 52 when there is either no pressure, or equalpressure, applied to the cylinder 55 on both sides of the piston 56. Inthe event, however, that the pressure on the spring side of the cylinder59 is reduced below that on the piston rod side, the piston 56 is movedaway from the bellcrank 52, to thereby permit the bellcrank 52 to dropthe piston stop 51 into an engaged position with the piston stop stem45.

When there is no pressure on the confining and locatingapparatus of FIG.6, the spring 59 moves the piston ss toward the valve portion ll, thusmoving the bcllcrank 52 and raising the piston stop 51. When brakepressure is introduced into the housing or cavity 50, it normally tendsto push the piston away from the cavity 50 and lower the piston stop 511into its en gsged position. This however is prevented in normaloperation by the introduction of main reservoir pressure air on thespring side of the piston 56 within the cylinder 55. As is apparent, thepiston 56 has two diameters, the larger diameter being exposed to mainreservoir air and the smaller diameter exposed to brake pipe air. Whenthe two pressures are equal, the force on the effectively larger springside of the piston 56 causes the piston stop stem to be freed. Should itat any time be desired to engage the piston stop 51, the automatic testsequence program device actuates a solenoid which vents main reservoirpressure from the spring side of the cylinder 55, allowing the brakepipe pressure to move the piston back and engage the piston stop stem.

Observation of the position of the piston stop 51 and of the piston stopstem 45 is provided by a. transparent cylinder 60 (FIG. 6) and a viewingport 61 (as shown in FIG. 5). The cylinder 60 is provided with gasketsso that the cylinder is sealed pressuretight with respect to the cavity50 when pressure is applied to the nuts 49 or to the pressure plate at.

AUTOMATIC SYSTEM Program Control Device:

The program device for the system of the invention includes lOtSseparate channels. The program itself is perforated into a 5-inch papertape, and the perforations are approximately thirty-thousandtha of aninch in diameter. The device reads this program as the tape progressesby means of a vacuum system. The vacuum switches can be individuallyactuated in accordance with the program. The tape, progresses atapproximately 50 inches per minute and the tape for an AB serviceportion takes approximately 4 minutes to complete theftest. The tapehowever, is only 12 feet long, since during part of the test time themachine automatically stops itself and restarts. It is in effect a realtime system, where the machine waits for feedback signals to sequencethe events. The machine under its own control can stop the progress ofthe tape. Through combined functions of the various pressure-sensingdevices the machine can also stop itself while it is waiting for thepressure to rise or drop to a given level. Timing functions of themachine can also be accomplished by timing impulses in the tape itself.Since the rate of progress of the tape is fixed it is possible toprecisely control the timing of function simply by the control of thedistance between two impulses. A combination of this and a series oftimed relay stops provide any desired interval oftime.

ADAPTA'IIQNS FOR ABC AND ABD VALVES For the ABC valves the only changeswhich are necessary are to exchange the paper tape program and to maltca manual setting of the pressure difference switches. These adjustmentsare very simple and quick to make since they require only setting twomanually adjustable pointers so that the pressure switches will operateat the predetermined and desired pressure differentials. No tools areneeded for this adjustment nor does anything have to be opened ordismantled. The adjustment knobs protrude through the faces of thesepressure difference switches and as the operator turns the knobs he cansee the motion of the guide hands and thus position them properly.

Aao VALVES ABD VALVE EMERGENCY PORTION The same test plate is used forABD emergency portion as for the AB. However because the vent valveopening is offset approximately three-fourths of an inch from theposition of the AB vent valve hole it is necessary to insert theoffsetting platform in the hollow rod. plunger of the test plate.

3 in automating the AB service portion test, for example, there are twotests, number 9, the pistonreturn spring, and number 4, quick serviceexhaust test, which are costly to automate. Therefore the sequence oftests is rearranged doing instead of test 1 first, number 9 and then 4and then 1. This allows the operator to make three manual observations,two for the piston return spring and one for the quick service blow. ineffect, in the piston return spring test, the operator observes throughthe window 61 of the piston stop housing 46 on two occasions'when thepiston 45 moves. As soon as it moves he activates the go button on theprogram device and the machine automatically makes its "go-no-go"reading and prints out the results. Test number 4 calls for anobservation to be certain that there is a 3- second blow occuring at thequick service exhaust part of the AB valve. The mechanism for sensingthis blow and timing it for three seconds is also expensive to automate,since the blow coming out the exhaust hole is extremely light and sinceit is difficult to construct a probe or sensing device which could readthe blow coming from the rectangular hole in the back cover. One of thereasons for this is the variety of different valve back covers availableand the fact that there is no regularity in the casting which wouldguarantee a good sealing for sensing this pressure blow. By placingthese tests at the beginning, the operator makes the three observationswithin the first l5 seconds of the test, and then is free for otheractivities, such as running a second test rack or installing shippingcovers etc.

OPERATING TIMES COMPARISONS WITH MANUAL RACK, ETC.

A fair average time for manual operation of an AB service portion fairaverage time for manual operation of an AB service portion is about 20minutes. This is the traditional method wherein the operator bolts theservice portion to the test plate and performs the entire test manuallyand makes all observations of flow meters and gauges manually. The testconsole makes the complete test in approximately 5 minutes. The onlymanual operations are when the operator installs the portion on thestuds of the test plate and places the clamping device into position. Healso pushes the restart button three times in the service portion wherehe makes manual observations. These are finished in about 45 seconds andafter that the operator need not be in attendance.

POSSlBlLlTlES OF TESTING OTHER DEVICES The test console itself iscapable of automating the test for any device for which there is a testplate, e.g. any device which 8 MAINTENANCE AND REPAIR The rack ismanufactured largely from standard production line components. Thesolenoid valves are standard llO volt solenoids, two-way and three-way.The relays similarly are low-cost, standard two-pole double-throwrelays, or 1 10 volts, and 24 volts.

Thus, itis apparent that there has been provided, according to theinvention, apparatus which fully satisfies the aims, ob-

lo jects, and advantages set forth earlier. While the subcomponentsdescribed in detail above are particularly useful with a fully automaticor partly automatic test stand, it is evident, however, that thesecomponents may equally find utility with conventional manual airbraketest stands.

lclaim as my invention:

l. A clamping device for clamping railroad airbrake portions to a teststand, comprising:

a bracket member having air test conduits therein for communicating withsaid airbrake portion,

means for removabiy mounting said airbrake portion to one side of saidbracket member,

pivotable carriage means having pivot means on one end and movableperpendicularly of said bracket members abutment means on the other endof said carriage means and abutting said airbrake portion remote fromsaid bracket member,

and means for applying pressure from the pivot end of said carriagemeans to said bracket member whereby the abutment end of said carriagemeans compresses said airbrake portiontoward said bracket member tothereby clamp the two together.

2. Device of claim 1 including a replaceable mounting plate intermediatesaid bracket member and said airbrake portion.

3. Device of claim 1 wherein said carriage means comprises a pair ofspaced apart generally C-shaped members straddling said bracket memberand said airbrake portion.

4. Device of claim 1 wherein said pivot means comprises a pair ofaxially aligned journaled members, one on each side of said carriagemeans, and bearing means in a pair of crosshead members.

5. Device of claim 1 wherein said means for applying pressure comprisesfluid pressure means.

6. Device of claim 1 wherein the center of gravity of the combination ofsaid carriage means, said abutment means, and said pressure-applyingmeans is located above said pivot means and on the side of said abutmentend of said carriage means when said combination is horizontal and onthe side of said pivot end when said combination is vertical, so thatsaid carriage means remains horizontal when in a valve-engaged positionand remains vertical when in a valve-disengaged position.

7. A clamping device for clamping railroad airbrake per tions to a teststand, comprising:

a bracket member having air test conduits therein for communication withsaid airbrake portion,

an adapter plate removabiy securable to said bracket member forengagement with said airbrake portion,

a plurality of airbrake-portion-engaging studs on said adapter plateextending perpendicularly from said bracket member,

a pivotable clamp carriage for clamping said airbrake portion to saidadapter plate and thereafter to said bracket member, said clamp carriagehaving an abutment end and a pivot end,

said abutment end having a plurality of abutments in axial register witheach of said studs,

pivot means for said clamp carriage movable perpendicularly to saidbracket member,

and fluid pressure-operated means carried by the pivot end of said clampcarriage for applying clamping pressure to said bracket member andtoward said abutment end.

8. Device of claim 7 wherein said plurality of abutments are carried byan equalizing plate pivotably connected to said abutment end, thepivotable connection being equidistant from each ofssid abutments.

1. A clamping device for clamping railroad airbrake portions to a teststand, comprising: a bracket member having air test conduits therein forcommunicating with said airbrake portion, means for removably mountingsaid airbrake portion to one side of said bracket member, pivotablecarriage means having pivot means on one end and movable perpendicularlyof said bracket members abutment means on the other end of said carriagemeans and abutting said airbrake portion remote from said bracketmember, and means for applying pressure from the pivot end of saidcarriage means to said bracket member whereby the abutment end of saidcarriage means compresses said airbrake portion toward said bracketmember to thereby clamp the two together.
 2. Device of claim 1 includinga replaceable mounting plate intermediate said bracket member and saidairbrake portion.
 3. Device of claim 1 wherein said carriage meanscomprises a pair of spaced apart generally C-shaped members straddlingsaid bracket member and said airbrake portion.
 4. Device of claim 1wherein said pivot means comprises a pair of axially aligned journaledmembers, one on each side of said carriage means, and bearing means in apair of crosshead members.
 5. Device of claim 1 wherein said means forapplying pressure comprises fluid pressure means.
 6. Device of claim 1wherein the center of gravity of the combination of said carriage means,said abutment means, and said pressure-applying means is located abovesaid pivot means and on the side of said abutment end of said carriagemeans when said combination is horizontal and on the side of said pivotend when said combination is vertical, so that said carriage meansremains horizontal when in a valve-engaged position and remains verticalwhen in a valve-disengaged position.
 7. A clamping device for clampingrailroad airbrake portions to a test stand, comprising: a bracket memberhaving air test conduits therein for communication with said airbrakeportion, an adapter plate removably securable to said bracket member forengagement with said airbrake portion, a plurality ofairbrake-portion-engaging studs on said adapter plate extendingperpendicularly from said bracket member, a pivotable clamp carriage forclamping said airbrake portion to said adapter plate and thereafter tosaid bracket member, said clamp carriage having an abutment end and apivot end, said abutment end having a plurality of abutments in axialregister with each of said studs, pivot means for said clamp carriagemovable perpendicularly to said bracket member, and fluidpressure-operated means carried by the pivot end of said clamp carriagefor applying clamping pressure to said bracket member and toward saidabutment end.
 8. Device of claim 7 wherein said plurality of abutmentsare carried by an equalizing plate pivotably connected to said abutmentend, the pivotable connection being equidistant from each of saidabutments.